Collector nozzle for slidable gates

ABSTRACT

A collector nozzle for slidable gates used to control teeming of liquid metal from a bottom-pour vessel. A collector nozzle is a tube which is mounted integrally with the gate and extends downwardly therefrom to confine the stream of metal discharging through an opening in the gate. A conventional collector nozzle is formed of a tube of a refractory which has a relatively high thermal conductivity and which resists erosion, but is subject to having droplets of the teemed metal solidify at its discharge end and form objectionable &#39;&#39;&#39;&#39;bugs.&#39;&#39;&#39;&#39; The invention provides a removable tip for attachment to the discharge end of the tube. The tip is a refractory of lower thermal conductivity less likely to have &#39;&#39;&#39;&#39;bugs&#39;&#39;&#39;&#39; form thereon.

United States Patent Shapland, Jr. et al.

COLLECTOR NOZZLE FOR SLIDABLE GATES lnventors: Earl P. Shapland, ,1 r., Champaign,

111.; James T. Shapland, Wilkins Township, Allegheny County, Pa.

United States Steel Corporation, Pittsburgh, Pa. by Earl P. Shapland Filed: Mar. 1, 1973 Appl. No.: 337,251

Assignee:

US. Cl 222/561, 222/567, 251/144 Int. Cl B22d 37/00 Field of Search 222/561, 566, 569, 567;

References Cited UNITED STATES PATENTS 7/1927 l-lassal et al 222/566 UX 7/1962 French 222/566 UX 10/1966 Yates..... 222/566 UX 12/1967 Crowe 222/566 UX 5/1970 Bick et a1 4. 222/561 FQREIGN PATENTS OR APPLlCATlONS 2/1958 Great Britain 222/566 Great Britain 222/569 Primary Examiner-Allen N. Knowles Assistant Examiner-David A. Scherbel Attorney, Agent, or FirmWalter P. Wood [57] ABSTRACT A collector nozzle for slidable gates used to control teeming of liquid metal from a bottom-pour vessel. A collector nozzle is a tube which is mounted integrally with the gate and extends downwardly therefrom to confine the stream of metal discharging through an opening in the gate. A conventional collector nozzle is formed of a tube of a refractory which has a relatively high thermal conductivity and which resists erosion, but is subject to having droplets of the teemed metal solidify at its discharge end and form objectionable bugs. The invention provides a removable tip for attachment to the discharge end of the tube. The tip is a refractory of lower thermal conductivity less likely to have bugs form thereon.

7 Claims, 4 Drawing Figures Great Britain 222/5 69.

PAIENIEB BUT I 5 IBM F/G. 3n

COLLECTOR NOZZLE FOR SLIDABLE GATES This invention relates to an improved collector nozlie for slidable gates used to control teeming of liquid metal from a bottom-pour vessel.

In the slidable gate art, a collector nozzle" is a refractory tube which is mounted integrally with a gate and extends downwardly from an opening in the gate to confine the stream of metal as it is teemed through the opening and maintain a relatively tight stream. Reference can be made to our earlier joint application, Ser. No. 150,585, filed June 7, 1971, now abandoned for a showing of a slidable gate which is intended particularly for use on ladles and which is equipped with a collector nozzle. Our improved collector nozzle may be used to advantage on a gate constructed as shown in said application, although it is apparent the nozzle may be used as well with other forms of gate.

Conventional practice is to employ an erosionresistant refractory in a collector nozzle. The refractory at the upper portion of the nozzle immediately adjacent the gate must be capable of resisting erosion of a throttled pouring stream, and high-alumina refractories commonly are used. However, erosion-resistant refractories have a relatively high thermal conductivity which makes them less desirable for the lower portion or discharge end of the nozzle. Droplets of the teemed metal tend to solidify on the discharge end and form bugs which deflect the pouring stream. Sometimes such bugs drop off and contaminate the metal in the receiving vessel. The problem can be overcome by using a refractory of lower thermal conductivity at the discharge end of the nozzle than the refractory next to the gate, but the refractory at the lower portion of a nozzle thus constructed erodes more rapidly than the refractory at the upper portion. Since the gate and nozzle are integral, the whole piecemust be scrapped when any small portion is eroded or damaged to an extent that it is no longer serviceable.

An object of our invention is to provide an improved collector nozzle which has a removable and replaceable refractory tip at its lower end, whereby we can use different refractories in different portions of the nozzle, yet avoidthe need of scrapping the whole piece because of damage to a small portion at the discharge end.

A further object is to provide a replaceable tip which can be attached to a collector nozzle to afford a discharge end not likely to be affected by bugs.

In the drawing:

FIG. 1 is a vertical sectional view of a portion of a slidable gate mechanism equipped with our improved collector nozzle;

FIG. 2 is a side elevational view on line IIII of FIG.

FIG. 3 is a fragmentary view similar to FIG. 1, but showing a modification; and

FIG. 4 is another fragmentary view similar to FIG. 1, but showing another modification.

FIG. I shows diagrammatically a top plate and a slidable gate 12 which form part of a mechanism for controlling teeming of liquid metal from a bottom-pour vessel. The remainder of the mechanism, as well as the vessel itself, may be of any standard or desired construction, for example as shown in the aforementioned application. The top plate 10 is formed of a refractory body 13 and a metal frame 14 and has a teeming opening 15. The gate 12 is formed of refractory body 16, a

metal frame 17, and a layer of refractory cement 18 between the body and frame. The gate includes an integral downwardly extending collector nozzle 19. The nozzle is formed of an erosion-resistant refractory tube 20, a metal casing 21 surrounding the tube, and a layer 22 of refractory cement between the tube and casing. The tube extends through an opening in the refractory body 16 of the gate, and its upper end is flush with the upper face of the gate. The refractory of the tube commonly is high alumina, that is, about 70 to 95 percent by weight A1 0 but other materials may be used, such as magnesia or a magnesia-chrome mixture.

In accordance with our invention, the lower portion of the collector nozzle 19 includes a removable and replaceable tip 23. The tip is formed of a refractory ring 24, a metal casing 25 surrounding the ring, and a layer 26 of refractory cement between the ring and casing. The ring forms a continuation of tube 20 and the upper face of the ring has a counterbore 27 which receives the bottom of the tube. The tip is attached to the main portion of the nozzle with a metal band 28 which surrounds the parts at their juncture. The ends of the band are held together with a bolt 29. FIG. 3 shows a modification in which the tip is attached with spring clips 30. The clips are integral with the casing 25a and extend upwardly therefrom, where they are received in a groove 31 in the casing 21a. FIG. 4 shows another modification in which the tip is threadedly attached to the main portion of the nozzle. The two casings 21b and 25bhave interengaging screw threads 32.

The refractory of ring 24 has a lower thermal conductivity than the refractory of tube 20. If an alumina refractory is used in the ring, the maximum A1 0 content is about 70. percent by weight. Examples of refractories of which we may form the rings are fire clay and rebonded fused silica. There is a much less likelihood of droplets of the teemed metal solidifying on these refractories than on the erosion-resistant refractory of the tube 20. The tip 23 is a small piece and can be replaced at relatively low cost when it becomes eroded or damaged. A number of tips formed of different refractories can be stocked, and a tip of the optimum refractory for teeming any particular metal can be installed.

We claim:

1. In a slidable gate which includes a refractory gate body having an opening, and a collector nozzle mounted integrally with said body and extending downwardly from said opening, said nozzle comprising a tube of refractory which has a relatively high thermal conductivity and which resists erosion during teeming of liquid metal, a metal casing surrounding said tube, and a layer of refractory cement between said tube and said casing, the improvement which comprises a shortlength removable and replaceable tip and means attaching said tip to the lower end of said tube, said tip being formed of a ring of refractory of lower thermal conductivity than the refractory of said tube and a metal casing surrounding at least the upper portion of said ring, whereby said tip resists formation of bugs on the discharge end of said nozzle and can be replaced when eroded without replacing the remainder of said tube.

2. A gate as defined in claim 1 in which said attaching means includes a band surrounding said tip and the portion of said tube thereabove.

formed of a high-alumina refractory.

6. A gate as defined in claim 5 in which the refractory of said ring has a maximum alumina content of about percent by weight and is selected from the group which consists of fire clay and rebonded fused silica.

7. A gate as defined in claim 1 in which said tip is of uniform length throughout its circumference. 

1. In a slidable gate which includes a refractory gate body having an opening, and a collector nozzle mounted integrally with said body and extending downwardly from said opening, said nozzle comprising a tube of refractory which has a relatively high thermal conductivity and which resists erosion during teeming of liquid metal, a metal casing surrounding said tube, and a layer of refractory cement between said tube and said casing, the improvement which comprises a short-length removable and replaceable tip and means attaching said tip to the lower end of said tube, said tip being formed of a ring of refractory of lower thremal conductivity than the refractory of said tube and a metal casing surrounding at least the upper portion of said ring, whereby said tip resists formation of bugs on the discharge end of said nozzle and can be replaced when eroded without replacing the remainder of said tube.
 2. A gate as defined in claim 1 in which said attaching means includes a band surrounding said tip and the portion of said tube thereabove.
 3. A gate as defined in claim 1 in which said attaching means includes spring clips integral with said second-named casing, said first-named casing having a groove receiving said clips.
 4. A gate as defined in claim 1 in which said attaching means includes interengaging screw threads on the two casings.
 5. A gate as defined in claim 1 in which said tube is formed of a high-alumina refractory.
 6. A gate as defined in claim 5 in which the refractory of said ring has a maximum alumina content of about 70 percent by weight and is selected from the group which consists of fire clay and rebonded fused silica.
 7. A gate as defined in claim 1 in which said tip is of uniform length throughout its circumference. 